Flow diverter effect of LVIS stent on cerebral aneurysm hemodynamics: a comparison with Enterprise stents and the Pipeline device

The white-collar sign after Neuroform Atlas stent-assisted coil embolization of unruptured intracranial aneurysms

PURPOSE

Although stent-assisted technique is expected to help provide a scaffold for neointima formation at the orifice of the aneurysm, not all aneurysms treated with stent-assisted technique develop complete neointima formation. The white-collar sign (WCS) indicates neointimal tissue formation at the aneurysm neck that prevents aneurysm recanalization. The aim of this study was to explore factors related to WCS appearance after stent-assisted coil embolization of unruptured intracranial aneurysms (UIAs).

METHODS

A total of 59 UIAs treated with a Neuroform Atlas stent were retrospectively analyzed. The WCS was identified on digital subtraction angiography (DSA) 1 year after coil embolization. The cohort was divided into WCS-positive and WCS-negative groups, and possible predictors of the WCS were explored using logistic regression analysis.

RESULTS

The WCS appeared in 20 aneurysms (33.9%). In the WCS-positive group, neck size was significantly smaller (4.2 (interquartile range (IQR): 3.8-4.6) versus 5.4 (IQR: 4.2-6.8) mm, p = .006), the VER was significantly higher (31.8% (IQR: 28.6%-38.4%) versus 27.6% (IQR: 23.6%-33.8%), p = .02), and the rate of RROC class 1 immediately after treatment was significantly higher (70% vs 20.5%, p < .001) than in the WCS-negative group. On multivariate analysis, neck size (odds ratio (OR): 0.542, 95% confidence interval (CI): 0.308-0.954; p = .03) and RROC class 1 immediately after treatment (OR: 6.99, 95% CI: 1.769-27.55; p = .006) were independent predictors of WCS appearance.

CONCLUSIONS

Smaller neck size and complete occlusion immediately after treatment were significant factors related to WCS appearance in stent-assisted coil embolization for UIAs using the Neuroform Atlas stent.

Clinical and Angiographic Outcomes of Endovascular Treatment for Acute Intracranial Vertebral Artery Dissecting Aneurysms Using Double-Overlapping Stents : Low-Profile Visualized Intraluminal Support within Enterprise Stents

OBJECTIVE

The use of reconstructive treatment with a double-overlapping stents has proven to be effective and safe in the current treatment of intracranial vertebral artery dissecting aneurysms (VADAs). We employed a combination of overlapping stents, using low-profile visualized intraluminal support (LVIS) within the Enterprise stent. This combination was chosen to minimize the outward bulging of the inner LVIS by overlapping it with the Enterprise stent while maintaining flow diversion and stability. This study aimed to evaluate the clinical and angiographic outcomes following the use of double-overlapping stents with LVIS within the Enterprise stent for the treatment of VADAs.

METHODS

From March 2016 to January 2022, total 28 patients with unruptured VADAs were treated with the double-overlapping stent technique using LVIS within an Enterprise stent in our institute. The Enterprise stent was deployed first, followed by the LVIS stent. Patient clinical and angiographic characteristics, procedural complications, and follow-up outcomes were retrospectively reviewed.

RESULTS

All 28 patients (18 males and 10 females) were successfully treated with double-overlapping stent deployment. There were no procedural complications or new neurological deficits in any patient. Of the 28 patients, four VADAs had posterior inferior cerebellar artery involvement. Procedure-related parent artery occlusion did not occur during the angiographic follow-up conducted 6 to 12 months after the procedure. Out of 28 patients, 24 showed complete healing, three had focal residual stenosis or dilatation with residual sac and only one had a residual dissecting flap with aneurysm. All patients, including the four patients, did not require any additional procedures. The postoperative modified Rankin scale scores were 0-1 for all patients.

CONCLUSION

A double-overlapping stent, with a flow-diversion effect, is a safe and effective treatment for patients with VADAs. In particular, when using the LVIS stent within an Enterprise stent, it minimizes the bulging of the inner LVIS stent while maintaining flow diversion and stability. Therefore, both can be effectively utilized as overlapping stents.

Y Stent-Assisted Coiling Technique for Bifurcation Aneurysms Using Double Neuroform® Stent: a Large Restrospective Series

BACKGROUND

Stent assisted coiling technique have shown to be an effective and safe endovascular strategy for wide neck bifurcation aneurysms in achieving greater packing, allowing the closure of the aneurysm and preserving the parent arteries, compared to simple coiling.

MATERIAL AND METHODS

We conducted a retrospective analysis of 79 patients with cerebral aneurysms treated using 'Y'-configuration double Neuroform® stent-assisted coiling at our center from July 2009 to July 2022.

RESULTS

Of the 79 patients, 76% (60/79) were incidental unruptured cerebral aneurysm and 24% were patients treated for aneurysm recanalization of a previous ruptured aneurysm (19/79). The most frequent locations were anterior communicating artery (AComA) 44.3% (35/79) and middle cerebral artery (MCA) 32.9% (26/79). We found a complete and almost complete aneurysm occlusion (Raymond-Roy occlusion classification (RROC) 1 and 2): in 100% (79/79) in the angiography after procedure, in 97.6% (42/43) at the first follow-up at 6-8 months and 100% (57/57) at the first 1-2 years of follow-up. No mortality related to treatment was detected. We registered 2.5% (2/79) major ipsilateral strokes, one due to acute in stent thrombosis (patient had a mRS: 0 in follow up at 90 days) and a spinal anterior artery occlusion (patient had a mRS: 3 in follow up at 90 days).

CONCLUSION

The 'Y' stent-assisted coiling technique with double Neuroform® is a safe and effective technique for the treatment of wide-neck bifurcation aneurysms, with high rates of complete occlusion, preserving the permeability of the afferent and efferent arteries and low rate of complications.

Three-dimensional fusion imaging to assess apposition of low-profile visualized intraluminal support stent for intracranial aneurysm coiling

Objective

To investigate on three-dimensional (3D) fusion images the apposition of low-profile visualized intraluminal support (LVIS) stents in intracranial aneurysms after treatment and assess inter-rater reliability.

Materials and methods

Records of all patients with unruptured intracranial aneurysms who were treated with the LVIS stent were retrospectively accessed and included in this study. Two neurosurgeons evaluated the presence of malapposition between the vessel walls and the stent trunk (crescent sign) and the vessel wall and the stent edges (edge malappostion) on 3D fusion images. These images were high-resolution cone-beam computed tomography images of the LVIS stent fused with 3D-digital subtraction angiography images of the vessels. Associations between malapposition and aneurysm location were assessed by Fisher's exact test, and inter-rater agreement was estimated using Cohen's kappa statistic.

Results

Forty consecutive patients were included. In all patients, 3D fusion imaging successfully visualized the tantalum helical strands and the closed-cell structure of the nitinol material of the low-profile visualized intraluminal support. A crescent sign was observed in 27.5 % and edge malapposition in 47.5 % of the patients. Malapposition was not significantly associated with location (p = 0.23 crescent sign, p = 0.07 edge malapposition). Almost perfect (κ = 0.88) and substantial (κ = 0.76) agreements between the two raters were found for the detection of crescent signs and edge appositions, respectively.

Conclusions

3D fusion imaging provided clear visualization of the LVIS stent and parent arteries, and could detect malapposition with excellent inter-rater reliability. This technique may provide valuable guidance for surgeons in determining postoperative management.

Appraisal of the Flow Diversion Effect Provided by Braided Intracranial Stents

Objective: Comparison of the results of stent-assisted coiling (SAC) with braided stents (BS), flow diverters (FD), and laser-cut stents (LCS) to determine the relative flow-diverting capacity of BS (Leo baby and Accero). Methods: Saccular intracranial aneurysms treated by SAC and FD-assisted coiling were retrospectively evaluated. Aneurysm occlusion, as graded per Raymond-Roy score, was categorized as either recanalization/stable residual filling (Group A; lacking a flow diversion effect) or stable/progressive occlusion (Group B with a "flow diversion effect"). Factors predicting the flow diversion effect were evaluated. Results: Of the 194 aneurysms included, LCS, BS, and FD were used in 70 (36.1%), 86 (44.3%), and 38 (19.6%) aneurysms, respectively. Aneurysms treated by FD were larger, had wider necks, and were located on larger parent arteries (p < 0.01, 0.02, and <0.01, respectively). The mean imaging follow-up duration was 24.5 months. There were 29 (14.9%) aneurysms in Group A and 165 (85.1%) in Group B. Among a spectrum of variables, including sex, age, aneurysm size, neck width, parent artery diameter, follow-up duration, and stent type, the positive predictors for stable/progressive aneurysm occlusion were aneurysm size and placement of an FD or BS (p < 0.01 and p < 0.01, respectively, and were positive predictors over LCS: ORs 6.34 (95% CI: 1.62-24.76) and 3.11 (95% CI: 1.20-8.07), respectively) in multivariate analysis. Conclusions: The placement of BS was a predictor of flow diversion over laser-cut stents. However, the flow diversion effect was approximately half that of FDs, suggesting that BS may only be considered to have some (partial) flow diversion effects.

"Stent-within-a-Stent" technique for the endovascular treatment of giant aneurysm of basilar artery bifurcation: A case report

Stents have become very important devices in the treatment of intracranial aneurysms. Flow diverters as high metal coverage stents are developed for hemodynamic treatment of challenging intracranial aneurysms. High level of metal coverage can also be achieved by implementing regular stents telescopically one in another. We present the case of a patient successfully treated for giant aneurysm of basilar artery bifurcation by a "Stent-within-a-Stent" technique. After stent implantation, coil embolization was performed using multiple-sized platinum helical coils. Control angiography performed at the end of the procedure revealed aneurysm occlusion. After 3 years, the patient is fully neurologically recovered, without pyramidal deficit, independently active and able to work.

Endovascular Treatment of Intracranial Aneurysm: The Importance of the Rheological Model in Blood Flow Simulations

Hemodynamics in intracranial aneurysm strongly depends on the non-Newtonian blood behavior due to the large number of suspended cells and the ability of red blood cells to deform and aggregate. However, most numerical investigations on intracranial hemodynamics adopt the Newtonian hypothesis to model blood flow and predict aneurysm occlusion. The aim of this study was to analyze the effect of the blood rheological model on the hemodynamics of intracranial aneurysms in the presence or absence of endovascular treatment. A numerical investigation was performed under pulsatile flow conditions in a patient-specific aneurysm with and without the insertion of an appropriately reconstructed flow diverter stent (FDS). The numerical simulations were performed using Newtonian and non-Newtonian assumptions for blood rheology. In all cases, FDS placement reduced the intra-aneurysmal velocity and increased the relative residence time (RRT) on the aneurysmal wall, indicating progressive thrombus formation and aneurysm occlusion. However, the Newtonian model largely overestimated RRT values and consequent aneurysm healing with respect to the non-Newtonian models. Due to the non-Newtonian blood properties and the large discrepancy between Newtonian and non-Newtonian simulations, the Newtonian hypothesis should not be used in the study of the hemodynamics of intracranial aneurysm, especially in the presence of endovascular treatment.

Safety and effectiveness of the LVIS and LVIS Jr devices for the treatment of intracranial aneurysms: Final results of the LEPI multicenter cohort study

BACKGROUND

The Low profile visualized intraluminal support (LVIS)/LVIS Jr is a self-expanding braiding stent for the treatment of intracranial aneurysm. This study is to determine the safety and effectiveness of the LVIS/LVIS Jr for the treatment of intracranial aneurysms in a real-world setting.

METHODS

This prospective, observational, multicenter study enrolled patients with unruptured, ruptured and recanalized intracranial aneurysms treated with the LVIS stents, between February 2018 to December 2019. Primary endpoint was the cumulative morbidity and mortality rate (CMMR) assessed at 12 months follow-up (FU).

RESULTS

A total of 130 patients were included (62.3 % women, mean age 55.9 ± 11.4) on an intention-to-treat basis. Four patients (3.1 %) had 2 target aneurysms; 134 total aneurysms were treated. The aneurysms were mainly located on the middle cerebral artery (41/134; 30.6 %) and the anterior communicating artery (31/134; 23.1 %). The CMMR at 1 year linked to the procedure and/or device was 4.6 % (6/130). The overall mortality was 1.5 % (2/130), none of these deaths adjudged as being linked to the procedure and/or device. All aneurysms (134/134, 100 %) were successfully treated with LVIS stent and/or other devices. At a mean FU of 16.8 months post-procedure, complete/nearly complete occlusion was achieved in 112 aneurysms (92.6 %), and only 3 patients (2.5 %) required aneurysm retreatment.

CONCLUSION

This study provides evidence that the LVIS/LVIS Jr devices are safe and effective in the treatment of complex intracranial aneurysms, with very high rates of adequate occlusion at FU. These angiographic results are stable over time with an acceptable complication rate.

TRIAL REGISTRATION

ClinicalTrial.gov under NCT03553771.

Compatibility of the semijailing technique with extremely soft i-ED coils for ruptured blood blister-like and dissecting aneurysms: patient series

BACKGROUND

Optimal treatment options for ruptured blood blister-like aneurysms (BBAs) and dissecting aneurysms (DAs) have not yet been established. Endovascular treatment may achieve vessel reconstruction with the preservation of antegrade blood flow; however, securing curative hemostasis at the fragile rupture point remains a major concern.

OBSERVATIONS

Two ruptured BBAs and two ruptured DAs treated by stent-assisted coiling with the semijailing technique in the last 2 years are described herein. The devices used were braided stents and i-ED coils, which are new low-memory shape and extremely soft coils. Neither rebleeding nor ischemic complications were observed. All patients had a favorable outcome and showed no recurrence after treatment.

LESSONS

All aneurysms were treated without ischemic complications or rebleeding. The good compatibility of braided stents and the new concept coils in stent-assisted coiling by the semijailing technique provides insight into these intractable hemorrhagic vascular pathologies.

Low-Profile Visualized Intraluminal Support Junior Flow-Diversion Properties Used for Stabilization of a Superior Cerebellar Artery Pseudoaneurysm

BACKGROUND

Pseudoaneurysms of the posterior circulation pose a unique management challenge. The fragile nature of the pseudoaneurysm wall presents a high risk of rupture and demands treatment. Small vasculature, particularly distal in the posterior circulation, can preclude management with traditional flow diverters, where the alternative of vessel sacrifice is unacceptable. Small stents can have flow-diversion properties and can be used in these high-risk, difficult-to-access aneurysms.

METHODS

We describe a 40-year-old woman presenting with a ruptured dissecting right superior cerebellar artery pseudoaneurysm after minor trauma. Given the aneurysm's small size and morphology, it was not amenable to coiling and parent vessel sacrifice was potentially morbid. The pseudoaneurysm was initially stabilized with a Low-Profile Visualized Intraluminal Support Junior (LVIS Jr.) stent due to its reported flow-diverting properties.

RESULTS

At six-month follow-up the pseudoaneurysm was stable and the vasospasm had resolved. At this point, definitive treatment with a "FRED Jr." (Flow Re-Direction Endoluminal Device Junior) flow diverter was pursued. Complete obliteration of the pseudoaneurysm was seen at 12 months' follow-up after staged treatment.

CONCLUSIONS

Due to the unique challenges associated with ruptured pseudoaneurysms located on small-caliber vessels, the options for definitive treatment are limited. The small size of the LVIS Jr. stent and its flow-diverting properties make it a practical treatment option in a difficult situation. This case report provides further support for the flow-diverting properties of the LVIS Jr. and its potential application in the treatment of ruptured pseudoaneurysms in small-caliber intracranial vessels.

Single centre experience of stent-assisted coiling of wide-necked basilar tip aneurysms

OBJECTIVE

To report clinical and radiological follow-up outcomes of stent-assisted coiling of wide-necked basilar tip aneurysms and to evaluate the safety and efficacy of this treatment choice.

METHODS

A retrospective review was carried out of 19 patients with wide-necked basilar tip aneurysms in our institution between 2010 and 2020. The rates of perioperative complication, morbidity, mortality, imaging follow-up and re-treatment were analysed.

RESULTS

Our technical complication rate was 11% but did not result in treatment failure. The combined procedure related morbidity and mortality rate of the 19 patients who underwent stent assisted coiling was also 11%. 16 of 19 patients had undergone angiographic follow-up with a mean period of 32 months. 81% of patients with angiographic follow-up had a satisfactory occlusion (RROI or II) with 11% requiring re-treatment. Those requiring re-treatment were both treated with laser-cut stents; this is in contrast with no re-treatments required in the patients treated with braided stents.

CONCLUSION

Our report provides acceptable outcomes in wide-necked basilar termination aneurysms which are very challenging to treat. Aneurysms treated with braided stents had better efficacy outcomes than those with laser-cut stents.

ADVANCES IN KNOWLEDGE

Given the emergent and increasing utility of alternative endovascular techniques such as intrasaccular devices and flow diverters, real-world data are lacking on more conventional approaches such stent-assisted coiling, especially so in the posterior circulation. The associated relatively higher aneurysmal haemorrhagic risk in this location warrants further additional safety and efficacy data for this treatment approach, which this paper provides.

Safety and efficacy of braided stents as stent monotherapy for the treatment of small intracranial aneurysms

BACKGROUND

The safety and efficacy of low-profile braided stent as stent monotherapy require further investigation.

OBJECTIVE

To analyze patient outcomes after treatment with braided stents used as "light" flow diverters.

MATERIAL/METHODS

Retrospective study to evaluate the occlusion rate of aneurysms treated with braided stent and remodeling of covered side branches and perforators. Several factors potentially influencing aneurysm occlusion were analyzed.

RESULTS

Thirty-five aneurysms in 31 patients were included. Six aneurysms (17.1%) had an acute subarachnoid hemorrhage. Braided stent was used as retreatment among 9 previously coiled aneurysms (25.7%). A total occlusion was achieved in 18 aneurysms (51.4%), entry remnant in 3 aneurysms (8.6%), incomplete filling in 6 aneurysms (17.1%) and complete filling in 8 aneurysms (22.9%). None of the aneurysms ruptured during the follow-up period. Of 32 stents deployed, we observed 3 cases (9.4%) of asymptomatic mild stenosis and 3 cases (10.7%) of narrowing of covered branches among 28 covered arteries. There were no cases of perforator infarction and no mortality or permanent morbidity associated with the treatment. Moreover, aneurysms <2.5 mm, aneurysms with a neck <1.8 mm, those with a mean aspect-ratio of 1.4, and lateral wall aneurysms had a higher frequency of adequate occlusion.

CONCLUSION

Braided stents used as stent monotherapy appear to be sufficiently effective in the treatment of very small intracranial aneurysms, despite a lower overall occlusion rate compared to a standard flow diversion strategy. However, given the low morbidity rate, this strategy may be an alternative to flow-diverter stents for small and distally located lesions.

Endovascular treatment strategies and a new classification for multiple aneurysms of the ipsilateral ophthalmic segment of the internal carotid artery

OBJECTIVE

Aneurysms occurring in the ophthalmic segment (C6) of the internal carotid artery (ICA) have complex anatomy. This poses a challenge for the use of traditional open surgery, which is gradually being replaced by endovascular treatment (EVT). However, multiple aneurysm (MA) EVT, especially in MAs occurring ipsilaterally, has not been specifically described or discussed. The present study aimed to propose a more concise clinical classification standard for ipsilateral C6 ICA MAs and report on the clinical experience with EVT.

METHODS

The cases of 18 patients with ipsilateral C6 ICA MAs treated with EVT were retrospectively reviewed. The treatment results and procedure-related complications were recorded, and clinical and angiographic follow-ups were performed at least six months after surgery.

RESULTS

A total of 38 ipsilateral C6 ICA aneurysms were treated during the study period and classified into four main types and six total subtypes based on anatomical features. There was a failure to coil through the stent in one aneurysm, while the remaining 37 were successfully treated using various EVT methods. Of these, 36 were completely concluded. One aneurysm had a size reduction, and one had no changes during the angiographic follow-up. All Tubridge flow diverter stents were patent. All patients achieved satisfactory clinical outcomes and were independent at the final follow-up.

CONCLUSION

EVT may be safe and feasible for the treatment of C6 ICA MAs. Traditional stent-assisted coiling methods, the Willis covered stent, and the double-layered low-profile visualized intraluminal support stent all achieved favorable results. The flow diverter stent is also considered a safe and efficient option for selected aneurysms, but the visual deficit risk should be considered. The present study introduces a new EVT classification option based on the anatomical features of an aneurysm.

Long-Term Outcomes of Ruptured Blood Blister-Like Aneurysms with Multiple (≥2) Overlapping Stents and Coiling: A Single-Center Experience

OBJECTIVE

To evaluate the long-term feasibility of multiple overlapping stents (≥2) with or without coiling for treating blood blister-like aneurysms (BBAs).

METHODS

BBAs treated with stent-assisted coiling or stent-only therapy wasincluded. BBAs with atypical anatomical locations, other endovascular or surgical techniques performed, and delayed treatment (>48 hours) were excluded. Medical records of patients and procedures were retrospectively reviewed.

RESULTS

Seventeen patients with BBAs were identified, and 15 were treated with stent-assisted coiling and 2 with stent-only therapy. Triple overlapping stents were performed in seven patients, double stents in nine, and a single stent with coiling in 1. One patient experienced in-stent fibrin formation and received intra-arterial tirofiban. Complementary treatment was required in four patients. Three patients were initially treated with double (3/9) and 1 with triple stents (1/7). Three recurred in the acute period (≤6 weeks) and 1 recurred 14 months after treatment. Three of 17 patients with Hunt Hess grade 5 died early. Thirteen patients were available for long-term angiographic follow-up (13.8 ± 8.9 months). Final angiography showed complete aneurysm occlusion in all patients without in-stent stenosis or perforating vessel occlusion. Clinical follow-up data were available for all 14 surviving patients (66.8 ± 40.9 months). Eight patients had favorable outcomes, five had unfavorable outcomes, and 1 died of a subarachnoid hemorrhage-unrelated cause. Delayed infarct or hemorrhage was not documented.

CONCLUSIONS

Even in the era of flow diverter stents, the use of multiple overlapping stents with or without coiling can be a feasible alternative for treating ruptured BBAs.

Venous outflow-targeted coil embolization of direct carotid-cavernous fistulas

BACKGROUND

Coil embolization is the mainstay treatment for carotid-cavernous fistulas (CCFs). However, few studies have reported entire occlusion of engorged veins to interrupt venous outflow. We report our experience with venous outflow-targeted coil embolization of direct CCFs.

METHODS

We retrospectively reviewed all the patients diagnosed with direct CCFs treated with venous outflow-targeted coil embolization between November 2013 and February 2020. Venous outflow-targeted coil embolization of the CCFs was performed as follows. First, transarterial stent-assisted coil embolization of CCFs was performed. If the venous outflow to the engorged veins persisted after transarterial stent-assisted coil embolization, entire occlusion of the engorged veins and additional coil packing within the cavernous sinus were performed to interrupt the venous outflow.

RESULTS

Ten patients had undergone venous outflow-targeted coil embolization, 6 women (60%) and 4 men (40%). Transfemoral cerebral angiography showed high-flow, direct CCFs in all the patients. Venous outflow occurred through the superior ophthalmic vein (SOV) in all the patients and was completely interrupted by the entire occlusion of the engorged veins with fibered coils. Three patients (30%) had undergone additional treatment in a supplementary manner because of recurrent symptoms (chemosis in 1 patient, faint tinnitus in 2 patients) in the early postprocedural period (1 to 4 weeks). All the symptoms were resolved on follow-up. No additional recurrence was found during follow-up (1-75 months). No peri-procedural complications were encountered.

CONCLUSIONS

Venous outflow-targeted coil embolization of CCFs would be a safe and effective treatment method.

Braided stent-assisted coil embolization versus laser engraved stent-assisted coil embolization in patients with unruptured complex intracranial aneurysms

PURPOSES

Braided and laser-cut stents both are efficacious and safe for coiling intracranial aneurysms. The study aimed to compare outcomes following braided stent-assisted coil embolization versus laser engraved stent-assisted coil embolization in 266 patients who were diagnosed with unruptured intracranial aneurysms of different types and locations.

METHODS

Patients with unruptured complex intracranial aneurysms underwent braided (BSE cohort, n = 125) or laser engraved (LSE cohort, n = 141) stent-assisted embolization.

RESULTS

The deployment success rate was higher for patients of the LSE cohort than those of the BSE cohort (140 [99%] vs. 117 [94%], p = 0.0142). Seventy-one (fifty-seven percentages) and 73 (52%) were coil embolization procedure success rates of the BSE and the LSE cohorts. Periprocedural intracranial hemorrhage was higher in patients of the BSE cohort than those of the LSE cohort (8 [6%] vs. 1 [1%], p = 0.0142). Four (three percentages) patients from the LSE cohort and 3 (2%) patients from the BSE cohort had in-stent thrombosis during embolization. Permanent morbidities were higher in patients of the LSE cohort than those of the BSE cohort (8 [6%] vs. 1 [1%], p = 0.0389). Higher successful procedures (76% vs. 68%) and fewer postprocedural intracranial hemorrhage (0% vs. 5%) and mortality (0% vs. 5%) were reported for patients of the BSE cohort in posterior circulation aneurysmal location than those of the LSE cohort. Laser engraved stent has fewer problems with deployment and may have better periprocedural and follow-up outcomes after embolization.

CONCLUSIONS

Braided stent-assisted embolization should be preferred when the aneurysm is present in the posterior circulation.

Cervical radiculopathy due to extracranial vertebral artery dissection treated by stent placement with a flow diversion effect: illustrative case

BACKGROUND

Cervical radiculopathy due to extracranial vertebral artery dissection (VAD) is extremely rare. The disease is usually treated with conservative treatment because of its favorable prognosis. However, there is a possibility that conservative treatment may bring about no improvement in radiculopathy. Although stent placement with a flow diversion effect may be effective in such cases, there are no reported cases that were treated with stent placement.

OBSERVATIONS

A 40-year-old healthy man presented with severe right neck pain, right arm pain, and right arm weakness after cracking his neck. A neurological examination revealed right C5 radiculopathy. Neuroimaging studies revealed right extracranial VAD. The VAD compressed the right C5 nerve root. Although medications were administered, there was no improvement in the symptoms. He experienced severe radicular pain. The authors performed stent placement with a flow diversion effect 10 days after the onset of VAD. His radicular pain improved immediately after the procedure, and the remaining radiculopathy completely improved within 1 month. Follow-up angiography showed complete improvement of the VAD.

LESSONS

Stent placement with a flow diversion effect may be considered when radiculopathy that hinders a patient's daily life exists. Stent placement may bring about rapid improvement in radiculopathy, especially radicular pain.

Results of Double Low-Profile Visualized Intraluminal Support Blue Stenting for the Treatment of Fusiform Cerebral Aneurysms

BACKGROUND

The flow diversion technique is increasingly used for reconstructive endovascular treatment of fusiform cerebral aneurysms. Double stenting with the Low-profile Visualized Intraluminal Support (LVIS) Blue stent is one of the flow diversion techniques. The aim of this study was to analyze the clinical and angiographic outcomes of LVIS Blue double stenting for fusiform cerebral aneurysms.

METHODS

Between March 2016 and July 2020, double LVIS Blue stenting was attempted in 25 fusiform cerebral aneurysms. Patient medical records and radiological images were carefully reviewed.

RESULTS

The technical success rate was 100% (25/25). Six aneurysms (24.0%) were located in the anterior circulation and 19 aneurysms (76.0%) were located in the posterior circulation. Intraprocedural thromboembolic complications occurred in 1 patient (4.0%). During the follow-up period (30.8 ± 14.2 months), there were no deaths or delayed complications. The mean angiographic follow-up duration was 28.2 ± 12.8 months. Follow-up angiography revealed complete obliteration (O'Kelly-Marotta D) in 21 (84.0%) patients and near-complete obliteration (O'Kelly-Marotta C + 2 matched with Kamran-Byrne grade 3) in 2 (8.0%) patients. Two patients (8.0%) showed worsening of obliteration grades. One (4.0%) patient required retreatment. There was no significant in-stent stenosis or branch occlusion covered by stents.

CONCLUSIONS

Double stenting using LVIS Blue stents for the treatment of fusiform cerebral aneurysms is effective and safe.

Effects of stent-assisted coiling in comparison with flow diversion on intracranial aneurysms

Objective

The aim of this study was to investigate the efficacy and complications of stent-assisted coiling in comparison with flow diversion for wide-necked intracranial aneurysms.

Methods

Patients with wide-necked intracranial aneurysms who were treated with stent-assisted coiling or flow diversion were respectively, enrolled into the stent-assisted coiling or flow diversion treatment group. The clinical and angiographic data were analyzed.

Results

A total of 61 patients with intracranial aneurysms underwent stent-assisted coiling, including 35 (57.4%) female and 26 (42.6%) male patients with 21 (34.4%) ruptured and 40 (65.6%) unruptured aneurysms. Also, 53 patients underwent deployment of flow-diverting devices, including 30 (56.6%) female and 23 (43.4%) male patients with 25 (47.2%) ruptured and 28 (52.8%) unruptured aneurysms. Stent-assisted coiling was performed successfully in 60 patients with 63 stents deployed, and immediate aneurysm occlusion was complete occlusion in 38 (62.3%) aneurysms, residual neck in 12 (19.7%), and residual aneurysm in 10 (16.4%). Procedure-related complications included in-stent thrombosis in three (4.9%) patients, coil protrusion in three (4.9%), and re-rupture of one (1.6%) aneurysm, with a total complication rate of 11.5%. In the flow diversion group, a pipeline embolization device alone was deployed in each of the 24 (45.3%) patients, adjunctive coiling combined with a pipeline device in 29 (54.7%), and double pipeline devices in each of the 6 (11.3%) patients. Immediately after treatment, complete occlusion was achieved in 3 (5.7%) patients with adjunctive coiling, residual neck in 3 (5.7%), and residual aneurysm in 47 (88.7%). Procedure-related complications included aneurysm rebleeding in one patient (1.9%). Clinical and angiographic follow-up was performed 13–49 months (median 29) after the procedure for 49 (80.3%) patients with stent-assisted coiling, with complete aneurysm occlusion in 27 (55.1%) aneurysms, residual neck in 3 (6.1%), residual aneurysm in 5 (10.2%), and recurrence in 14 (28.6%). Follow-up was performed for 14–37 (median 25) months in 45 (84.9%) patients with flow diversion treatment, with complete occlusion in 39 (86.7%) patients, residual neck in 5 (11.1%), residual aneurysm in 1 (2.2%), and no aneurysm recurrence.

Conclusions

Stent-assisted coiling comes with more complications but fewer permanent aneurysm occlusions than flow diverters, and flow diverters are superior to stent-assisted coiling in the treatment of wide-necked intracranial aneurysms, especially in the long-term effect.

Stent-alone treatment of unruptured vertebral artery fusiform aneurysms: A comparison of flow diverter and conventional stents

Background

Treatment of vertebral artery fusiform aneurysms (VAFAs) is complex and controversial. This study aimed to compare the safety and efficacy between flow diverter and conventional stents in patients with VAFAs undergoing endovascular stent-alone treatment (SAT).

Methods

Thirty-six patients with 36 VAFAs who underwent SAT between January 2014 and December 2018 were retrospectively analyzed. Patient and aneurysm characteristics, procedural details, complications, and angiographic and clinical outcomes were compared between flow diverter stent patients (n = 22) and conventional stent patients (n = 14).

Results

More branches covered with stent were found in the conventional stent group (88.9 vs. 33.3%; p = 0.008). The number of stents placed was significantly higher in the conventional stent group (1.57 ± 0.76 vs. 1.09 ± 0.29; p = 0.016). The proportion of patients with significant or moderate stasis within the aneurysm immediately after stent placement was higher in the flow diverter stent group (95.5 vs. 57.1%; p = 0.004). The proportion of patients with complete obliteration or only a residual neck on follow-up angiography was significantly higher in the flow diverter stent group (86.3 vs 50.0%; p = 0.047). However, the incidence of parent artery stenosis or occlusion was also higher in the flow diverter stent group (27.3% vs. zero; p = 0.032). The rate of complications did not significantly differ between the groups.

Conclusions

SAT was safe and effective in patients with VAFAs. Flow diverter stents are associated with a significantly better complete occlusion rate than conventional stents; however, they are also associated with an increased risk of parent artery stenosis.

Stent implantation in a patient with non-hemorrhagic vertebral artery dissection associated with severe, continuously progressive stenosis in the posterior inferior cerebellar artery bifurcation region: A case report

Generally, the prognosis of non-hemorrhagic vertebral artery dissection is good. Treatment should be considered when stenosis progresses or when an aneurysm is formed. However, no clear treatment policy has been established. The purpose of this case report was to describe the treatment policy for non-hemorrhagic onset vertebral artery dissection with severe stenosis around the posterior inferior cerebellar artery (PICA) bifurcation and aneurysm, where stent placement in the vertebral artery was difficult. This report describes healing without complications with stent implantation in the PICA performed to treat non-hemorrhagic vertebral artery dissection with associated severe, continuously progressive stenosis in the PICA bifurcation region. A 36-year-old woman was examined at the authors’ hospital for persistent pain in the left posterior neck. Left vertebral arteriography revealed stenosis due to dissection around the PICA bifurcation and aneurysm formation at the distal position. Due to the progression of stenosis, there were concerns about PICA occlusion, and stent implantation in the vertebral artery was performed via the PICA. Neck pain ceased immediately after surgery, and 3 months later, cerebral angiography showed favorable patency of the PICA and decreased aneurysm size. This case suggests that stent implantation in the PICA might be a useful treatment option for non-hemorrhagic vertebral artery dissection with associated severe stenosis in the PICA bifurcation region.

Flow diversion effect of the leo braided stent for aneurysms in the posterior and distal anterior circulations: A multicenter cohort study

Background and purpose

The treatment of aneurysms located in the posterior and distal anterior circulations remains a challenge. Leo stents with a flow diversion (FD) effect may be a potential option, which needs to be clearly studied.

Methods

From January 2016 to October 2021, 133 patients with 145 aneurysms in the posterior and distal anterior circulations, treated with Leo stents, were retrospectively analyzed in three neurosurgical centers. Data on demographic information, aneurysm characteristics, procedural outcomes, postoperative course, and aneurysm occlusion were retrospectively analyzed.

Results

After immediate surgery, 90 aneurysms (60.1%) were in complete occlusion [Raymond-Ray Occlusion Class (RROC) 1 and O'Kelly Marotta (OKM) grade D], 29 aneurysms (20%) in good occlusion (RROC 2 and OKM grade C), 17.9% in incomplete occlusion (RROC 3a or OKM grade B), and no aneurysms in invalid occlusion (RROC 3b and OKM grade A). A total of 112 patients with 117 aneurysms received angiographic follow-up (mean 11.4 months), and the degree of occlusion showed a significant improvement (Z = 3.900, p < 0.001). The complete occlusion rate increased to 84.6% (99/117), while good and incomplete occlusion decreased to 6.8% (8/117) and 8.6% (10/117), respectively. A total of 14 cases (10.5%) presented narrowing of the parent artery, and nine cases (6.8%) had injured side branches. Cerebral hemorrhage occurred in four patients (3.0%), and symptomatic ischemic infarction occurred in six patients (4.5%). The final permanent morbidity (mCS ≥3) and mortality were 2.8% (3/133) and 0.8% (1/133), respectively. For 82 aneurysms treated by stent-assisted with coiling (SAC), large-sized, ruptured aneurysms (χ² = 7.767, p = 0.005) occurred. For 63 aneurysms treated by LEO stent monotherapy (LSM), multiple aneurysms, fusiform aneurysms (χ² = 18.958, p < 0.01), and/or small-sized aneurysms (Z = −2.692, p = 0.007) occurred.

Conclusions

Leo stents are safe and effective for aneurysms located in the posterior and distal anterior circulations. The overall degree of occlusion improved during a follow-up because of the FD effect of Leo stents. Aneurysms in these areas should be treated with personalized measures.

Vertebral Artery Perforation as a Periprocedural Complication of Coronary Angiography

Coronary angiography is a routinely performed intervention, with radial catheterization the recommended approach. We report a unique case of perforation of the right vertebral artery following coronary angiography that was successfully treated by endovascular management. (Level of Difficulty: Advanced.).

Case Series of Endovascular Therapy for Blood Blister-Like Aneurysm in Acute Phase

Objective

Blood blister-like aneurysms (BBAs) of the internal carotid artery are highly challenging to treat due to their variable morphology and tendency for rupture and regrowth. Here, we report a single-institution experience of endovascular therapy (EVT) for BBA treatment.

Methods

We retrospectively reviewed patients with ruptured BBA from 2006 to 2019. All patients in whom BBA was treated with EVT were included. Patients' aneurysmal characteristics, progression status, aneurysm occlusion on follow-up angiography, and modified Rankin Scale (mRS) score were recorded.

Results

A total of 11 patients (5 women and 6 men) with the mean age of 46 ± 10 years were included in this study. As initial treatment, 9 patients were treated with stent-assisted coiling (SAC). Immediate angiographic results showed that 2 cases were body filling, 4 were neck remnant, and 3 were complete obliteration. Perioperative ischemic complications were not observed. On postoperative day 1, 2 patients suffered from rerupture, and their prognoses were poor. Retreatments were performed in 5 patients. Parent artery occlusion (PAO) was performed in 6 patients including 2 initial treatments and 4 retreatments. Symptomatic infarction developed in 2 patients. In 3 patients, bypass in combination with PAO was performed. Clinical data revealed discharge mRS scores of 0-2 and 3-6 in 4 and 7 patients, respectively.

Conclusion

SAC is effective for the management of BBA. Careful follow-up and response are necessary after treatment with SAC.

Successful use of an LVIS device to treat unruptured distal aneurysm of the superior cerebellar artery at a vascular bifurcation

Background

Aneurysms of the distal superior cerebellar artery (SCA) account for only a small proportion of all cerebral aneurysms. Reports of the use of flow diverters (FDs) started to appear in 2013. We obtained good results from placement of a low-profile visualized intraluminal support device (LVIS) to treat unruptured distal aneurysm of the SCA at a vascular bifurcation.

Case Description

A 65-year-old man presented at our hospital with sudden peripheral facial nerve palsy and suspected subarachnoid hemorrhage. Investigational cerebral angiography revealed an aneurysm at the bifurcation of the caudal and rostral trunks of the SCA. An LVIS was placed with the aim of obtaining flow diversion, and cerebral angiography 6 months after this procedure showed disappearance of aneurysm with preservation of the distal SCA.

Conclusion

Twelve cases of the use of FDs to treat aneurysms of the SCA have been reported previously. However, none of those reports described FD use to treat an aneurysm at a vascular bifurcation, as in the present case. Our results suggested that LVIS placement with the aim of obtaining flow diversion may be useful for the treatment of aneurysms at such sites.

Association Between Aneurysmal Hemodynamics and Rupture Risk of Unruptured Intracranial Aneurysms

Background

Assessing rupture risk in patients with unruptured intracranial aneurysms (UIAs) remains challenging. Hemodynamics plays an important role in the natural history of intracranial aneurysms. This study aimed to compare aneurysmal hemodynamic features between patients with different rupture risk as determined by PHASES score.

Methods

We retrospectively examined 238 patients who harbored a solitary saccular UIA. Patients were stratified by rupture risk into low-, intermediate-, and high-risk groups according to PHASES score. Flow simulations were performed to compare differences in hemodynamics among the groups.

Results

Aneurysmal time-averaged wall shear stress (WSSa) and normalized WSS (WSSn) decreased progressively as PHASES score increased. WSSa and WSSn significantly differed among the low-, intermediate-, and high-risk groups (p < 0.001). WSSa was significantly lower in the high-risk group than the low-risk group (p < 0.001) and the intermediate-risk group (p = 0.004). WSSn was also significantly lower in the high-risk group than the low-risk group (p < 0.001) and the intermediate-risk group (p = 0.001).

Conclusions

Low WSS was significantly associated with higher risk of intracranial aneurysm rupture as determined by PHASES score, indicating that hemodynamics may play an important role in aneurysmal rupture. In the future, a multidimensional rupture risk prediction model that includes hemodynamic parameters should be investigated.

Successful carotid artery stenting with a double-layer micromesh stent for spontaneous extracranial internal carotid artery dissection: a case report

Extracranial internal carotid artery dissection is a relatively rare disease in Japan. We herein report a case of a 60-year-old woman with spontaneous left internal carotid artery dissection with a dilated and dissected cavity. Following the identification and measurement of the true and false lumens using intravascular ultrasound, a double-layer micromesh stent (Casper stent; Microvention, Terumo, Tustin, CA, USA) was deployed for post-dilation. No perioperative complications were observed, and the patient was discharged on postoperative day 6.

LVIS-within-enterprise double-stent procedure without coiling beneficial as treatment of unruptured vertebral artery dissecting aneurysms

Stenting of vertebral artery dissecting aneurysms (VADAs) may promote mural apposition of intimal flaps, preserving the patency of injured vessels. Moreover, stent deployment may serve to alter intra-aneurysm flow, inducing saccular thrombus formation, neointimal development, and remodeling of injured vessels. Although an overlapping multistent strategy with coiling has proven successful in this setting, yielding good anatomic and clinical outcomes, coiling may be technically infeasible in some VADAs with unfavorably configured circumferential elevations. Herein, we describe three patients with VADAs for whom coiling was deemed technically problematic. Each underwent double stenting (LVIS within Enterprise), without coil insertion, using local anesthesia. Conventional angiographic follow-up regularly disclosed excellent saccular occlusion and subsequent remodeling of stented arteries. LVIS-within-Enterprise double stenting may be of particular benefit in patients with VADAs, the Enterprise providing outer support to minimize stent bulging (as a fusiform aneurysm) as the inner LVIS reinforces flow diversion.

Hemodynamic Effects of Stent-Induced Straightening of Parent Artery vs. Stent Struts for Intracranial Bifurcation Aneurysms

Objective

This study aims to compare the hemodynamic impact of stent-mesh and stent-induced straightening of the parent artery in intracranial bifurcation aneurysms using finite element method simulation.

Material and Methods

Three intracranial bifurcation aneurysms treated with different stent-assisted coil embolization were evaluated. Simulation using the finite element method was conducted for Solitaire, LVIS and Neuroform stents. Four models of each stent were established, including a pre-treatment baseline, stenting without parent artery straightening (presented as stent-mesh effect), no-stent with parent artery reconstruction (to reveal the straightening impact), and stenting with straightening (categorized as Models I–IV respectively). Hemodynamic characteristics of the four models for each stent were compared.

Results

In the Neuroform stent, compared with the pre-treatment model (100%), the mean WSS decreased to 82.3, 71.4, and 57.0% in Models II-IV, velocity to 88.3, 74.4, and 62.8%, and high flow volume (HFV, >0.3 m/s) to 77.7, 44.0, and 19.1%. For the LVIS stent, the mean WSS changed to 105.0, 40.2, and 39.8% in Models II to IV; velocity to 91.2, 58.1, and 52.5%, and HFV to 92.0, 56.1, and 43.9%. For the Solitaire stent, compared with the pre-treatment model (100%), the mean WSS of Models II-IV changed altered by 105.7, 42.6, and 39.4%, sac-averaged velocity changed to 111.3, 46.6, and 42.8%, and HFV 115.6, 15.1, and 13.6%.

Conclusion

The hemodynamic effect of straightening the parent artery of intracranial bifurcation aneurysms by stenting was noticeably improved over stent mesh diversion in all three stents tested. Therefore stent-induced remodeling of the parent artery appears to be the best method of decreasing recurrence in intracranial bifurcation aneurysms.

Overlapping Pure LIVS Jr. Stents for Isolated Ruptured Dissecting Aneurysm of the Proximal Posterior Inferior Cerebellar Artery

We report our experience in treating a ruptured dissecting posterior inferior cerebellar artery (PICA) aneurysm. To our knowledge, this is the first reported case of overlapping stenting without coils for a ruptured dissecting aneurysm of the proximal PICA. A 66-year-old male patient presented with sudden altered mental state and a subarachnoid hemorrhage (SAH). The cerebral angiography revealed a long segmental dissecting aneurysm on proximal PICA. Overlapping stents were deployed to the dissecting site, and angiogram showed intact distal PICA flow and decreased contrast staining in the dissecting site. Successful flow diversion was achieved with stents. Procedure-associated complications did not occur. The patient’s postoperative course was uneventful. In follow-up cerebral angiography, dissecting aneurysm achieved complete remodeling. The decision that led to the choice of treatment is discussed.

Outcomes following aneurysmal coil embolization with intentionally shortened low-profile visible intraluminal support stent deployment

PURPOSE

Among all stents available for neuroendovascular therapy, the low-profile visible intraluminal support stent bears the highest metal coverage ratio. We deployed a low-profile visible intraluminal support stent with a delivery wire or/and microcatheter system push action to shorten the low-profile visible intraluminal support stent and thus achieve a flow diversion effect. We report our single-institution experience with the use of low-profile visible intraluminal support stents for intentionally shortened deployment (shortening group) and non-shortened deployment (non-shortening group) for unruptured intracranial aneurysms.

METHODS

We retrospectively reviewed the medical records of 130 patients with 131 intracranial aneurysms who were treated with low-profile visible intraluminal support stent-assisted coil embolization from February 2016-January 2019. All perioperative complications were noted. Every 6 months, we re-examined the patients with cerebral angiography or magnetic resonance angiography. The outcomes of aneurysm occlusion were evaluated by the modified Raymond-Roy occlusion classification. We used the finite element method and computational fluid dynamics to investigate the hemodynamics after shortened low-profile visible intraluminal support stent deployment.

RESULTS

Immediately after treatment, the modified Raymond-Roy occlusion classification was significantly better in the shortening group than in the non-shortening group (p<0.05). The latest angiographic outcomes showed the same tendency. Hemodynamic analysis by computational fluid dynamics suggested an adequate flow diversion effect with the use of our intentional shortening method.

CONCLUSIONS

Stent-assisted coil embolization using this technique showed good results of a high complete occlusion rate and low complication rate. These findings suggest that shortened low-profile visible intraluminal support stent deployment yields a flow diversion effect and may lead to early intra-aneurysmal thrombus formation.

Unruptured Aneurysmal Shrinkage of the Distal Posterior Inferior Cerebellar Artery Following Stent Jailing of the Arterial Orifice: A Case Report

A 57-year-old woman who presented with a sudden severe headache and subsequently diagnosed with a subarachnoid hemorrhage was referred to our hospital. CTA revealed a large irregularly shaped dissecting aneurysm of the right vertebral artery (VA) and a small round distal aneurysm of the right posterior inferior cerebellar artery (PICA), which originated just proximal to the VA aneurysm. We diagnosed the VA aneurysm as a ruptured aneurysm and performed endovascular treatment the day the patient was hospitalized. Because the left VA was aplastic, stent-assisted coiling was performed to preserve the blood flow of the right VA, following the administration of antiplatelets and heparin. The proximal part of the laser-cut closed-cell stent jailed the orifice of the right PICA. The postoperative course was uneventful, and she was discharged from the hospital 3 weeks later without any neurological deficits. The follow-up VA angiogram revealed complete disappearance of the distal PICA aneurysm 17 months after stent jailing. Flow reduction by stent jailing of the arterial orifice is considered to be the main mechanism of aneurysmal shrinkage. Jailing of the orifice of the cerebral artery using even a low-metal-coverage stent may cause arterial flow reduction, which may shrink a distal aneurysm.

Low-profile visualized intraluminal support stent for the endovascular treatment of traumatic intracranial internal carotid artery pseudoaneurysms

Optimal treatment strategies for traumatic intracranial internal carotid artery (ICA) pseudoaneurysms are controversial. The low-profile visualized intraluminal support (LVIS) device is a braided stent with a metal coverage rate between traditional laser cut stents and flow diversion devices. We report here our therapy strategy using the LVIS stent-assisted coiling for treatment of traumatic intracranial ICA pseudoaneurysms. Patients with traumatic intracranial ICA pseudoaneurysms treated by the LVIS stent-assisted coiling in our center between January 2015 and June 2021 were reviewed. The complications, radiographic, and clinical outcomes of these patients were analyzed. A total of 12 patients with 12 pseudoaneurysms were included. The mean maximum aneurysm diameter was 6.2 ± 3.1 mm. Nine patients had a subarachnoid hemorrhage; five patients with Hunt-Hess grade III and four patients with grade IV. All procedures were successfully performed without intraoperative complications. Immediate postoperative angiogram showed that six (50%) aneurysms were Raymond grade 1, four (33.3%) were grade 2, and two (16.7%) were grade 3. Postoperative multiple cerebral infarction occurred in two patients because of vasospasm. Of the ten patients with angiographic follow-up (mean, 29.9 months), two received additional coiling because of recanalization of the pseudoaneurysm, and all aneurysms were completely obliterated at the last examination of the patients. During the clinical follow-up period (mean, 26.8 months), the overall mortality and morbidity were 25% (3/12) and 8.3% (1/12), respectively. LVIS stent-assisted coiling was a feasible approach for the treatment of traumatic ICA pseudoaneurysms.

Blister-like aneurysm of the anterior communicating artery treated with only Low-profile Visualized Intraluminal Support Junior stent

Background:

Endovascular treatment is becoming a mainstream treatment for blister-like aneurysms in recent years. Blister-like aneurysms are usually located in the internal carotid artery, whereas that of the anterior communicating artery (AcomA) are very rare. We report the first case of blister-like aneurysm of AcomA that was treated solely with a neck bridging stent that resulted in complete occlusion without complication.

Case Description:

A 50- year- old woman was admitted to our hospital due to a subarachnoid hemorrhage. Digital subtraction angiography showed a very small aneurysm in the dorsal side of the AcomA. We considered it a blister-like aneurysm based on its size and shape. She underwent endovascular treatment under general anesthesia on day 15 after vasospasm period. Dual antiplatelet therapy was administrated 1 week prior. A Low-profile Visualized Intraluminal Support Junior stent was implanted from the left A2 to the right A1, covering the AcomA. The postoperative course was uneventful, and she was discharged with no neurological deficit. The aneurysm remained unchanged on postoperative day 14; however, complete occlusion was achieved 3 months after the treatment.

Conclusion:

Monotherapy with a neck bridging stent is an effective treatment option for blister-like aneurysms. Treatment with a single stent could achieve complete occlusion especially if the aneurysms occur elsewhere than the internal carotid artery. We should consider immediate additional treatment if the aneurysm grows within 1 month after initial treatment.

Hemodynamic analysis for endovascular treatment in small unruptured intracranial aneurysms: a matched comparison study of flow diverter versus LVIS

BACKGROUND

We compared the treatment of small unruptured intracranial aneurysms (UIAs) with flow diverter and LVIS-assisted coiling to determine the effects of hemodynamic changes caused by different stent and coil packing in endovascular treatment.

METHODS

Fifty-one UIAs in 51 patients treated with pipeline embolization device (PED) were included in this study and defined as the PED group. We matched controls 1:1 and enrolled 51 UIAs who were treated with LVIS stent, which were defined as the LVIS group. Computational fluid dynamics were performed to assess hemodynamic alterations between PED and LVIS. Clinical analysis was also performed between these two groups after the match.

RESULTS

There was no difference in procedural complications between the two groups (P = 0.558). At the first angiographic follow-up, the complete occlusion rate was significantly higher in the LVIS group compared with that in the PED group (98.0% vs. 82.4%, P = 0.027). However, during the further angiographic follow-up, the complete occlusion rate in the PED group achieved 100%, which was higher than that in the LVIS group (98.0%). Compared with the LVIS group after treatment, cases in the PED group showed a higher value of velocity in the aneurysm (0.03 ± 0.09 vs. 0.01 ± 0.01, P = 0.037) and WSS on the aneurysm (2.32 ± 5.40 vs. 0.33 ± 0.47, P = 0.011). Consequently, the reduction ratios of these two parameters also showed statistical differences. These parameters in the LVIS group showed much higher reduction ratios. However, the reduction ratio of the velocity on the neck plane was comparable between two groups.

CONCLUSIONS

Both LVIS and PED were safe and effective for the treatment of small UIAs. However, LVIS-assisted coiling produced greater hemodynamic alterations in the aneurysm sac compared with PED. The hemodynamics in the aneurysm neck may be a key factor for aneurysm outcome.

Hemodynamic Investigation of the Effectiveness of a Two Overlapping Flow Diverter Configuration for Cerebral Aneurysm Treatment

Flow diverters (FDs) are widely employed as endovascular treatment devices for large or wide-neck cerebral aneurysms. Occasionally, overlapped FDs are deployed to enhance the flow diversion effect. In this study, we investigated the hemodynamics of overlapping FDs via computational fluid dynamics (CFD) simulations. We reproduced the arterial geometry of a patient who had experienced the deployment of two overlapping FDs. We utilized two stent patterns, namely the patterns for one FD and two overlapping FDs. We calculated the velocity, mass flow rate, wall shear stress, and pressure loss coefficient as well as their change rates for each pattern relative to the no-FD pattern results. The CFD simulation results indicated that the characteristics of the blood flow inside the aneurysm were minimally affected by the deployment of a single FD; in contrast, the overlapping FD pattern results revealed significant changes in the flow. Further, the velocity at an inspection plane within the aneurysm sac decreased by up to 92.2% and 31.0% in the cases of the overlapping and single FD patterns, respectively, relative to the no-FD pattern. The simulations successfully reproduced the hemodynamics, and the qualitative and quantitative investigations are meaningful with regard to the clinical outcomes of overlapped FD deployment.

Short- and Long-Term Safety and Efficacy of Self-Expandable Leo Stents Used Alone or with Coiling for Ruptured and Unruptured Intracranial Aneurysms: A Retrospective Observational Study

To assess the efficacy and safety of the Leo stent used alone or with coiling to treat complex intracranial aneurysms (IAs) not eligible for simple or balloon-assisted coiling, this single-center retrospective study included consecutive adults with ruptured or unruptured IAs treated in 2011-2018 by stenting with or without coiling. The indication for stenting was IA complexity precluding simple or balloon-assisted coiling. Extensive data on the patients, IAs, antiplatelet treatments, procedures, and outcomes over the first 36 months were collected. Risk factors for early complications (univariate analysis) and delayed ischemia (multivariate analysis) were sought. We include 64 patients with 66 IAs. The procedural success rate was 65/66 (98.5%). Obliteration was Raymond Roy class I or II for 85% of IAs. Six patients died including four of the 12 patients presenting with subarachnoid hemorrhage, which was the only significant risk factor for early major complications. At 1 month, 45/64 (69%) had no disabilities. No rebleeding was reported. Ischemia was detected by routine MRI in 20 (35%) of the 57 patients with long-term data and was asymptomatic in 14. The stent-within-a-stent configuration was the only independent risk factor for ischemia. The Leo stent used alone or with coils to manage challenging IAs was associated with a high procedural success rate and complete or nearly complete IA obliteration of 85% of IAs. The high frequency of ischemia is ascribable to our use of routine serial MRI. In patients with bleeding, the Leo stent was associated with an excess risk of early, major, intracranial complications, as compared to patients without bleeding. Long-term follow-up was marked by the occurrence of ischemic events in the vascular territory of the stent, mostly silent.

Radical treatment of ruptured dissecting aneurysm on the P1 segment with monotherapy using multiple LVIS stents

The standard endovascular treatment for ruptured dissecting aneurysm is a parent artery occlusion. However, this treatment is unsuitable when the artery of the lesion gives off perforating vessels that supply blood to critical regions or when the collateral flow cannot be expected due to the sacrifice of the parent artery. Here, we present an infrequent case of ruptured dissecting aneurysm on P1 segment of the posterior cerebral artery. The aneurysm had little sac for coiling and the artery of the lesion had some perforator branches; thus, we selected the monotherapy with three overlapping low-profile visualised intraluminal support stents as radical treatment, which resulted in prompt obliteration of the aneurysm. The patient was fully recovered at 3 months after the procedure. Previous studies have reported the effectiveness of multiple stents alone for dissecting aneurysms, whereas this case showed that overlapping stents may also be effective on the P1 segment.

Computational Study of Hemodynamic Changes Induced by Overlapping and Compacting of Stents and Flow Diverter in Cerebral Aneurysms

Purpose: The flow diversion effect of an intracranial stent is closely related to its metal coverage rate (MCR). In this study, the flow diversion effects of Enterprise and low-profile visualized intraluminal support (LVIS) stents are compared with those of a Pipeline flow diverter, focusing on the MCR change. Moreover, the changes in the flow diversion effect caused by the additional manipulations of overlapping and compaction are verified using computational fluid dynamics (CFD) analysis. Methods: CFD analysis was performed using virtually generated stents mounted in an idealized aneurysm model. First, the flow diversion effects of single Enterprise, LVIS, and Pipeline devices were analyzed. The Enterprise and LVIS were sequentially overlapped and compared with a Pipeline, to evaluate the effect of stent overlapping. The effect of compacting a stent was evaluated by comparing the flow diversion effects of a single and two compacted LVIS with those of two overlapped, uncompacted LVIS and uncompacted and compacted Pipeline. Quantitative analysis was performed to evaluate the hemodynamic parameters of energy loss, average velocity, and inflow rate. Results: Statistically significant correlations were observed between the reduction rates of the hemodynamic parameters and MCR. The single LVIS without compaction induced a reduction in all the hemodynamic parameters comparable to those of the three overlapped Enterprise. Moreover, the two overlapped, uncompacted LVIS showed a flow diversion effect as large as that induced by the single uncompacted Pipeline. Compacted stents induced a better flow diversion effect than uncompacted stents. The single compacted LVIS induced a flow diversion effect similar to that induced by the two uncompacted LVIS or single uncompacted Pipeline. Conclusions: The MCR of a stent correlates with its flow diversion effect. Overlapping and compaction can increase the MCR of an intracranial stent and achieve a flow diversion effect as large as that observed with a flow diverter.

Risk Factors for Recanalization after Coil Embolization

The aim of our study was to identify risk factors for recanalization 6 months after coil embolization using clinical data followed by computational fluid dynamics (CFD) analysis. Methods: Firstly, clinical data of 184 patients treated with coil embolization were analyzed retrospectively. Secondly, aneurysm models for high/low recanalization risk were generated based on ROC curves and their cut-off points. Afterward, CFD was utilized to validate the results. Results: In multivariable analysis, aneurysm filling during the first embolization was an independent risk factor whilst packing density was a protective factor of recanalization after 6 months in patients with aSAH. For patients with unruptured aneurysms, packing density was found to be a protective factor whilst the aneurysm neck size was an independent risk factor. Complex flow pattern and multiple vortices were associated with aneurysm shape and were characteristic of the high recanalization risk group. Conclusions: Statistical analysis suggested that there are various factors influencing recanalization risk. Once certain values of morphometric parameters are exceeded, a complex flow with numerous vortices occurs. This phenomenon was revealed due to CFD investigations that validated our statistical research. Thus, the complex flow pattern itself can be treated as a relevant recanalization predictor.

Midterm Outcomes After Low-Profile Visualization Endoluminal Support or Atlas Stent-Assisted Coiling of Intracranial Aneurysms: A Propensity Score Matching Analysis

BACKGROUND

The interplay of various commercially available stents during coil embolization of intracranial aneurysms and their ultimate impact are subject to debate.

OBJECTIVE

To compare midterm outcomes of Low-Profile Visualization Endoluminal Support (LVIS) (MicroVention Inc) and Atlas (Stryker) stent-assisted coiling procedures.

METHODS

A total of 459 intracranial aneurysms subjected to coil embolization using LVIS (n = 318) or Atlas stents (n = 141) between April 2015 and December 2019 were eligible for study. To assess occlusive status postembolization, magnetic resonance angiography and/or conventional angiography were used. The Raymond classification was applied to categorize recanalization. Our analysis was propensity score matched according to probability of stent type deployed.

RESULTS

Eventually, 41 aneurysms (8.9%) displayed recanalization (minor, 28; major, 13) 6 mo after coiling. Patient age (P = .018), sex (P = .015), aneurysmal location (P < .001), and type of aneurysm (P < .001) differed significantly by group. Overall and major recanalization rates at midterm were similar in both groups (9.1% and 8.5% vs 3.1% and 2.1%, respectively), and there was no significant difference even after 1:1 propensity score matching (odds ratio [OR] = 0.75 [P = .514] and OR = 0.75 [P = .706], respectively).

CONCLUSION

In stent-assisted coil embolization of intracranial aneurysms, midterm outcomes of LVIS and Atlas device groups were similar, despite theoretic LVIS superiority. Further randomized comparative studies are needed to confirm our findings.

AngioSuite-Assisted Volume Calculation and Coil Use Prediction in the Endovascular Treatment of Tiny Volume Intracranial Aneurysms

Methods

Thirty-three consecutive patients with 34 TVIAs were prospectively recruited and treated with endovascular techniques. The volume of TVIAs and the required length of coils were calculated by the AngioSuite software before embolization. The treatment efficacy of TVIAs was assessed using the Raymond scale (Rs) and the modified Rankin scale (mRs).

Results

Of the 34 aneurysms with an average volume of 7.16 mm³, 13 aneurysms were treated with sole coil embolization, 19 by stent-assisted embolization, and 2 by balloon-assisted embolization. The average coil length was 5.32 cm, and the average packing density was 41.21%. The immediate DSA showed that total occlusion (Rs = 1) was achieved in 15 aneurysms, subtotal (Rs = 2) in 9, and partial (Rs = 3) in 11. Total occlusion was achieved in 30 aneurysms and subtotal in the other 4 aneurysms at 6-month follow-up. Baseline volume and diameter of aneurysms were significantly correlated with the coil length (r = 0.801, P < 0.001; r = 0.711, P < 0.001).

Conclusions

Coil embolization of TVIAs was easy to achieve high packing density. According to the data from AngioSuite, relative few coils can increase the safety in procedure and stenting may reduce risk of aneurysmal recurrence.

Non-visualizable stent-occlusion after treatment of a fusiform PCA-aneurysm-a case report

We report the case of a 17-year-old woman with extensive subarachnoidal hemorrhage due to a ruptured fusiform aneurysm of the right PCA (posterior cerebral artery). Endovascular treatment was successfully performed using a LVIS-EVO-Stent (Microvention Incorporation, Tustin, USA) as well as several coils. Short-term angiographic follow-up demonstrated extensive aneurysm progression and dilatation of the coil package, the stent could no longer be visualized and was not passable. Despite excellent distal vascular perfusion, a non-visible stent occlusion was suspected and subsequent occlusion of the patent artery was performed. We conclude that rapid progression of fusiform aneurysms after stent-assisted coiling may lead to expansion of the coil packages and non-assessability of the stent. Even with excellent distal perfusion, a stent-occlusion should be suspected in these cases. Therefore, we suggest short-term angiographic follow-up, especially after deploying multiple coil packages in fusiform aneurysms.

Evaluation of Two Fast Virtual Stenting Algorithms for Intracranial Aneurysm Flow Diversion

BACKGROUND

Endovascular treatment of intracranial aneurysms (IAs) by flow diverter (FD) stents depends on flow modification. Patient-specific modeling of FD deployment and computational fluid dynamics (CFD) could enable a priori endovascular strategy optimization. We developed a fast, simplistic, expansion-free balls-weeping algorithm to model FDs in patientspecific aneurysm geometry. However, since such strong simplification could result in less accurate simulations, we also developed a fast virtual stenting workflow (VSW) that explicitly models stent expansion using pseudo-physical forces.

METHODS

To test which of these two fast algorithms more accurately simulates real FDs, we applied them to virtually treat three representative patient-specific IAs. We deployed Pipeline Embolization Device into 3 patient-specific silicone aneurysm phantoms and simulated the treatments using both balls-weeping and VSW algorithms in computational aneurysm models. We then compared the virtually deployed FD stents against experimental results in terms of geometry and post-treatment flow fields. For stent geometry, we evaluated gross configurations and porosity. For post-treatment aneurysmal flow, we compared CFD results against experimental measurements by particle image velocimetry.

RESULTS

We found that VSW created more realistic FD deployments than balls-weeping in terms of stent geometry, porosity and pore density. In particular, balls-weeping produced unrealistic FD bulging at the aneurysm neck, and this artifact drastically increased with neck size. Both FD deployment methods resulted in similar flow patterns, but the VSW had less error in flow velocity and inflow rate.

CONCLUSION

In conclusion, modeling stent expansion is critical for preventing unrealistic bulging effects and thus should be considered in virtual FD deployment algorithms. Also endowed with its high computational efficiency and superior accuracy, the VSW algorithm is a better candidate for implementation into a bedside clinical tool for FD deployment simulation.

Microsurgical Clipping of Carotid-Ophthalmic Tandem Aneurysms: Case Report and Surgical Nuances

Tandem intracranial aneurysms (TandIAs) are rare but inherently complex, and special technical considerations are required for their surgical management. The present case highlights the key surgical aspects of two carotid-ophthalmic TandIAs incidentally found in a 60-year-old female. Both the aneurysms were superiorly projecting, regular in size, and involved the left ophthalmic segment of the internal carotid artery (ICA). The minimum distance between the necks was 3 mm. The patient underwent microsurgery because of the reported major complications rate of the endovascular treatment in the case of a very short minimum distance between the TandIAs. After cervical ICA exposure, both the aneurysms were excluded through a pterional approach. Intradural anterior clinoidectomy and unroofing of the optic canal allowed the mobilization of the left optic nerve. The more distal aneurysm was clipped before the opening of the distal dural ring of the ICA. The proximal aneurysm was clipped with two straight clips stacked perpendicular to the ICA. A small remnant was intentionally left to avoid the stenosis of the ophthalmic artery. Postoperative angiography showed the exclusion of both the aneurysms with a small dog-ear of the more proximal one. The patient was discharged neurologically intact and, after one year, the remnant remained stable. Microsurgical clipping is a definitive and durable treatment for carotid-ophthalmic TandIAs. In the case of a very short minimum distance between the aneurysms, the distal one should be clipped first to make the anterior clinoidectomy, opening of the distal dural ring of the ICA, and clipping of the more proximal aneurysm easier.

Coil embolization with overlapping horizontal low-profile stents to treat a giant thrombosed fetal posterior cerebral artery aneurysm using contralateral approach through anterior communicating artery: Case report

Background

The treatment of internal carotid artery (ICA) - posterior communicating artery aneurysms (ICPC aneurysms) is challenging when a fetal posterior cerebral artery (PCA) arises from the saccular neck. This complex angioarchitecture renders endovascular approaches difficult. Giant thrombosed IC-PC aneurysms are also hard to treat by endovascular coiling because its flow-diversion effect is insufficient.

Case Description

We report the first case of a ruptured giant thrombosed IC-PC aneurysm associated with a fetal PCA that was successfully treated by coil embolization with retrograde overlap horizontal stenting using low-profile stents introduced through the contralateral ICA. The aneurysm was completely occluded and follow-up MRI scans demonstrated the reduction of the aneurysmal size.

Conclusion

Our technique is advantageous because low-profile stents can be used to treat lesions not accessible with flow-diverter stents due their presence in complex angioarchitectures, and overlap stenting may have flow-diversion effects that can result in the complete occlusion of giant thrombosed aneurysms.

Stent-in-stent technique for the management of blood blister-like basilar apex aneurysms

Blood blister-like basilar apex aneurysms are rare thin-walled vascular lesions with a poorly defined aneurysmal neck. We present two patients with ruptured blister aneurysms of the basilar apex who were treated using the stent-in-stent technique. Long-term follow-up showed persistent and complete occlusion of the aneurysms without radiographically or neurological complications. There is no optimal treatment of choice for the basilar apex blood blister-like aneurysms. Double- or triple-stent placement using the stent-in-stent technique can be a safe and feasible option for these uncommon and challenging intracranial aneurysms.

Endovascular Treatment of Intracranial Aneurysms Using the Novel Low Profile Visualized Intraluminal Support EVO Stent: Multicenter Early Feasibility Experience

Purpose

Low-profile, self-expandable stents have broadened therapeutic options available for definitive treatment of intracranial aneurysms. The novel Low-Profile Visualized Intraluminal Support (LVIS) EVO stent extends upon the success of its predecessor, the LVIS Jr stent, aiming to enable higher visibility and greater opening ability within a self-expandable and fully retrievable microstent system. In this study, we aim to report the early safety and feasibility experience with the LVIS EVO stent.

Materials and Methods

A multicenter, retrospective, observational study was conducted on patients who had intracranial aneurysms treated with the LVIS EVO stent across 3 Australian neurovascular centers between February 2020 and September 2020. Short-term technical and clinical outcomes were evaluated.

Results

A total of 22 LVIS EVO stents were successfully implanted to treat 15 aneurysms (3 ruptured, 12 unruptured) in 15 patients. Aneurysms ranged from 2 mm to 35 mm in dome height. The LVIS EVO stent was used for stent-assisted coiling in 11 patients and flow diversion in 4 patients. There were no device-related procedural complications. There were 2 cases of peri-procedural symptomatic thromboembolic complications and no procedure-related mortality. At early radiological follow up, 10 patients had complete occlusion, 4 patients had small neck remnants, and 1 patient who was managed with flow diversion had a residual aneurysm.

Conclusion

Early experience with the LVIS EVO stent demonstrated safety and feasibility for stent-assisted coiling as well as flow diversion for intracranial aneurysms. In this heterogeneous cohort, including ruptured, complex, and large aneurysms, all cases were technically successful.

The effect of Dean, Reynolds and Womersley numbers on the flow in a spherical cavity on a curved round pipe. Part 2. The haemodynamics of intracranial aneurysms treated with flow-diverting stents

The flow in a spherical cavity on a curved round pipe is a canonical flow that describes well the flow inside a sidewall aneurysm on an intracranial artery. Intracranial aneurysms are often treated with a flow-diverting stent (FDS), a low-porosity metal mesh that covers the entrance to the cavity, to reduce blood flow into the aneurysm sac and exclude it from mechanical stresses imposed by the blood flow. Successful treatment is highly dependent on the degree of reduction of flow inside the cavity, and the resulting altered fluid mechanics inside the aneurysm following treatment. Using stereoscopic particle image velocimetry, we characterize the fluid mechanics in a canonical configuration representative of an intracranial aneurysm treated with a FDS: a spherical cavity on the side of a curved round pipe covered with a metal mesh formed by an actual medical FDS. This porous mesh coverage is the focus of Part 2 of the paper, characterizing the effects of parent vessel Re, De and pulsatility, Wo, on the fluid dynamics, compared with the canonical configuration with no impediments to flow into the cavity that is described in Part 1 (Chassagne et al., J. Fluid Mech., vol. 915, 2021, A123). Coverage with a FDS markedly reduces the flow Re in the aneurysmal cavity, creating a viscous-dominated flow environment despite the parent vessel Re > 100. Under steady flow conditions, the topology that forms inside the cavity is shown to be a function of the parent vessel De. At low values of De, flow enters the cavity at the leading edge and remains attached to the wall before exiting at the trailing edge, a novel behaviour that was not found under any conditions of the high-Re, unimpeded cavity flow described in Part 1. Under these conditions, flow in the cavity co-rotates with the direction of the free-stream flow, similar to Stokes flow in a cavity. As De increases, the flow along the leading edge begins to separate, and the recirculation zone grows with increasing De, until, above De ≈ 180, the flow inside the cavity is fully recirculating, counter-rotating with respect to the free-stream flow. Under pulsatile flow conditions, the vortex inside the cavity progresses through the same cycle - switching from attached and co-rotating with the free-stream flow at the beginning of the cycle (low velocity and positive acceleration) to separated and counter-rotating as De reaches a critical value. The location of separation within the harmonic cycle is shown to be a function of both De and Wo. The values of aneurysmal cavity Re based on both the average velocity and the circulation inside the cavity are shown to increase with increasing values of De, while Wo is shown to have little influence on the time-averaged metrics. As De increases, the strength of the secondary flow in the parent vessel grows, due to the inertial instability in the curved pipe, and the flow rate entering the cavity increases. Thus, the effectiveness of FDS treatment to exclude the aneurysmal cavity from the haemodynamic stresses is compromised for aneurysms located on high-curvature arteries, i.e. vessels with high De, and this can be a fluid mechanics criterion to guide treatment selection.

Endovascular treatment of vertebral and basilar artery aneurysms with low-profile visualized intraluminal support device

Background

The Low-profile Visualized Intraluminal Support (LVIS) device is a self-expanding, nitinol, single-braid, closed-cell device that was recently developed for endovascular embolization of intracranial aneurysms. However, current knowledge regarding the use of LVIS devices to treat vertebral and basilar artery aneurysms is limited. We aimed to evaluate the feasibility, efficacy, and safety of the LVIS device for treating vertebral and basilar artery aneurysms.

Methods

Between January 2015 and December 2017, patients with vertebral and basilar artery aneurysms treated using LVIS stents were enrolled in this study. We analyzed patients’ demographic, clinical and aneurysmal characteristics, procedural details, complications, and angiographic and clinical follow-up results.

Results

We identified 63 patients with 64 vertebral and basilar artery aneurysms who underwent treatment with (n = 59) or without (n = 5) LVIS stenting, including 10 patients with ruptured aneurysms. Forty-one aneurysms were located at the vertebral artery, and 23 at the basilar artery. Intraprocedural-related complications developed in three (4.8%) patients, while none of these patients developed morbidities or died during follow-up. Three patients developed post-procedural complications (4.8%). Two patients experienced ischemic events immediately post-procedure. A minor permanent morbidity developed in one of the two patients (1.6%). The mortality rate was 1.6%, for that the patient died of brainstem hemorrhage after 1 month of follow-up. At a mean follow-up of 12.5 months, 39/43 (90.7%) patients had stable or improved aneurysms, and four (9.3%) had recanalized.

Conclusions

LVIS device of vertebral and basilar artery aneurysms may be an acceptable safety profile and may represent a reasonable treatment option in the short-term. Long-term and larger cohort studies are necessary to validate our results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02180-1.